// Copyright 2004-2021 Castle Project - http://www.castleproject.org/
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

namespace Castle.DynamicProxy.Generators.Emitters.SimpleAST
{
	using System;
	using System.Reflection;
	using System.Reflection.Emit;

	internal class NewInstanceExpression : IExpression
	{
		private readonly IExpression[] arguments;
		private ConstructorInfo constructor;

		public NewInstanceExpression(ConstructorInfo constructor, params IExpression[] args)
		{
			this.constructor = constructor ?? throw new ArgumentNullException(nameof(constructor));
			arguments = args;
		}

		public NewInstanceExpression(Type target)
		{
			constructor = target.GetConstructor(Type.EmptyTypes) ?? throw new MissingMethodException("Could not find default constructor.");
			arguments = null;
		}

		public void Emit(ILGenerator gen)
		{
			if (arguments != null)
			{
				foreach (var exp in arguments)
				{
					exp.Emit(gen);
				}
			}

			gen.Emit(OpCodes.Newobj, constructor);
		}
	}
}